(1) Field of the Invention
The invention relates to a mold casing for the manufacture, i.e. production of molded bodies, in particular concrete pipes, said casing being readied for the manufacture of said bodies by being moved into a closed manufacturing position and being opened, for purposes of releasing the finished molded bodies, from said manufacturing position, two mutually displaceable mold casing segments opening and closing said mold casing by means of a securing device securing the mold casing in its manufacturing position, said securing device moreover including at least one latch mounted on one of said mold casing segments, further a latch mating-element which is mounted on the particular other mold casing segment, the minimum of one latch being displaceable by means of a drive element between a locked position corresponding to the mold casing manufacturing position wherein it latches onto an associated latch mating-element, and an unlocked position wherein the locking engagement is eliminated.
(2) Description of Related Art
Such mold casings are used in particular to manufacture reinforced or unreinforced concrete pipes that illustratively are used in waste water pipe lines. To manufacture a concrete pipe the mold casing is deposited in its closed state, wherein illustratively it may exhibit a substantially cylindrical geometry, onto a manufacturing table of a production machine such as is known for instance from the brochure “SOUVERAEN, Symbiosis of Experience and Inventiveness” issue denoted by W&P-JB-LeR-VN1-4/96.2.D by Baumgärtner GmbH Maschinenfabrik. When in the production machine, the closed mold casing is filled with concrete which thereupon is compacted by a compression tool moving inside the mold casing and along its longitudinal axis against the inner walls of said casing. It is also known to make concrete pipes by filling concrete into a mold cavity between the mold casing and a mold core and then to compact said concrete by vibrations induced by a shaking tool.
In both cases the mold casing containing the finished concrete pipe which as yet has not cured shall be removed from the production machine and be moved to a storage site and left there for curing. After the mold casing has been opened to facilitate releasing, this casing is removed from the concrete pipe. On account of the size and weight of the mold casings, their transportation into and out of the production machine as well as in the manufacturing hall in general requires using cranes, fork lifts and the like.
The most common mold casings regardless of the particular kind of manufacture are both the “spring mold casings” and the “folding mold casings”.
Within the scope of the present specification, the expression “spring mold casing” denotes a mold casing exhibiting a substantially continuous circumferential mold wall that is interrupted only by a slot running through the longitudinal end faces of this casing. By means of the securing device mounted on both mold casing segments adjoining the slot, the mold casing may be spread apart to facilitate releasing and it may be constricted again in preparation for the manufacture of the next concrete pipe. In the light of the above discussion, “expansion” and “constriction” with respect to a spring mold casing correspond to the above cited “opening” and “closing” of the mold casing. It must be borne in mind in this regard that expanding the mold casing does not mandatorily entail that the mold cavity thereby shall have been made accessible from the outside through the slot. Instead said slot also may be closed by overlapping mutually adjoining mold casing segments.
On the other hand and within the scope of the present invention, a “folding mold casing” denotes a mold casing comprising at least two mold casing segments articulating on each other in pivoting manner. Illustratively these may be two substantially semi-cylindrical mold casing segments. However the mold casing of the invention also may consist of a larger number of mold casing segments, for instance three, where two quarter-circle mold-casing segments are linked in folding manner to a semi-circular mold casing segment and may be interconnected by the securing device. In this design the mutually linked mold casing segments are pivoted away from each other for the “opening” function and they shall be pivoted again toward each other for the “closing” function and thereupon be secured by the securing device.
Compared to the spring mold casings, the folding mold casings offer the advantage of less stressing the manufacturing scene. Spring mold casings require in particular to be removed “at the head” for the release function, that is, from above, from the finished concrete pipe, and this operation assumes an appropriate lift system as well as appropriate height of the manufacturing hall. Folding mold casings on the other hand may be removed in simple manner laterally from the finished concrete pipe. Moreover “at the head” releasing also is more time-consuming because the mold casing must move at least twice through a path corresponding to the length of the pipe.
In all modes of manufacturing and mold casing designs cited above, the complex operation of the securing device shall be a drawback. Conventionally the minimum of one latch shall be adjusted manually, electrically, hydraulically or pneumatically between its locked and unlocked positions. This adjustment requires in-house personnel made available for that purpose or it must be carried out by labor entrusted with inserting the mold casing into the production machine, its operation and the subsequent mold casing removal from said machine. As regards electrical, hydraulic or pneumatic adjustment, appropriate power units and supply hookups for them must be made available. Moreover valuable operating time is lost by connecting and disconnecting the power units and by operating them. In summary, operating the securing device entails considerable expenditure with respect to machinery and/or personnel and/or time, such a drawback being especially disadvantageous in the mass production of concrete pipes.